Sonic transducer apparatus

ABSTRACT

This invention relates generally to means of utilizing in a work environment a high-power, high-Q electromechanical transducer; and particularly means of loading a high-power electromechanical transducer, that is, coupling a high-power electromechanical transducer to a tool in a work environment.   D R A W I N G

United States Patent Inventors Robert C. McMas ter;

Charles C. Libby, Columbus; flildegard M. Minchenko, Reynoldsburg, Ohio Appl. No. 815,245 Filed Mar. 13,1969 Patented Jan. 26, 1971 I Assignee 1 The been! of Trustees of the Ohio State University Columbus, out

an institution in Iligher Learning at our SONIC TRANSDUCER APPARATUS a Claim, 4 Draw Figs.

U.S.Cl. sic/8.2, 310/83, 310/26 m. m no" woo Field orsemh 310/82,

References Cited UNITED STATES PATENTS 3,184,842 5/1965 Maropis 310/82 3,302,044 1/1967 Lynnworth 310/82 3,370,186 2/1968 Antonevich 3 l0/8.2 3,394,274 7/1968 .lacke 3 1 0/82 Primary Examiner-J. D. Miller Assistant Examiner-Mark O. Budd AnorneyAnthony D. Cennamo ABSTRACT: This invention relates generally to means of 4 utilizing in a work environment a high-power, high-Q electromechanical transducer; and particularly means of loading a high-power electromechanical transducer, that is, coupling a high-power electromechanical transducer to a tool in a work environment.

PATENTEDJMBIQYI 3558,93?

INVIENTOR. i ROBERT c. MCMASTER Q ,1 CHARLES C LIBBY MINCHENKO HILDEGARD M. I M m n SONIC TRANSDUCER APPARATUS This application is a divisional application of our copending patent application, Ser. No. 605,284, filed Dec. 28, I966 now US. Pat. No. 3,475,628.

There is disclosed in the copending application filed by Robert C. McMaster and Bemdt B. Dettloff, Ser. No. 508,812, filed Nov. 19, 1965, now US. Pat. No 3368085 for Transducer a sonic transducer that combines the driving element (piezoelectric) with the mechanical displacement amplifier (horn) in a novel way. The transducer therein disclosed is a high-Q transducer, exceptionally rugged, compact, and capableof carrying continuous wo'rk loads. Still, and most significantly, in another copending application, Ser. No. 571,490, filed Aug. l0, I966, now US. Pat. No. 3,396,285 for Electromechanical Transducer," by Hildegard M. Minchenkc, and assigned to the same Assignee, there is disclosed a transducer capable of delivering extremely high power, i.e., measurable in horsepower (or kilowatts) in an acoustical frequency range. The structural design of the transducer permits extraordinary power output from the driving elements. Through the clamping of the piezoelectric elements, both radially and longitudinally (axially), the acoustic stressesin the piezoelectric elements are always compressive, never tensileeven under maximum voltage excitation.

There is further disclosed in the copending application filed Nov. 19, 1965, for Sonic Generator, Ser. No. 508,804, by R. C. McMaster and C. C. Libby, and assigned to the same Assignee, a generator directed to the utilization of the generated force as a workload. More specifically there is disclosed a transmission-line means adapted for coupling one transducer to another for work transfer.

An electromechanical transducer such as that disclosed in the aforementioned copending applications will have fullpower capabilities when permitted to vibrate at its resonant frequency. It has now been found in practice that coupling the transducer to a workpiece, such as coupling the tip of the horn to a tool, will drastically reduce the power capabilities of the transducer if (1) the input frequency is constant and (2) the load characteristics (mass and compliance) constitutes a mismatch to the'resonant structure of the transducer. The ex planation for this is quite simple: the tool, when attached, becomes a part of the structure in general and the structure therefore will no longer resonate at the initial input frequency.

' BRIEF SUMMARY frequencies of the work surfaces.

OBJECTS It is accordingly an object of the present invention to provide novel method and means of utilizing a high-power transducer in a work environment.

Another object of the present invention is to provide novel method and means for coupling a high-Q transducer to tools in a work environment without a lossof power capability while utilizing a constant-frequency supply.

A further object of the present invention is to provide novel method and means of couplinga high-Q transducer to work surfaces having various configurations.

Still another object of the present invention is to provide means of delivering high-power to a work area that is simple, rugged and adaptable to most any type of high-power high-Q transducer.

Other objects and features of the present invention will become apparent from the following detailed description when taken in conjunction with the drawings in which:

BRIEF DESCRIPTIONS OF THE VIEWS OF THE DRAWINGS FIG. 1 is another embodiment ofthe present invention illustrating coupling of a high-power transducer to a thin sheet workpiece;

FIGS. 2 and 2a use other embodiments of the present invention illustrating coupling ofa high-power transducer to a tubular workpiece; and,

FIG. 3 is still another embodiment of the present invention illustrating coupling of a high-power transducer to a cone-type workpiece.

Referring now to FIGS. 1, 2, 2a, and 3, there is shown means of coupling the transducer to a workpiece. In the trans ducer modifications shown in these FIGS. there is significant difference in that a tool or adapter is fixed or permanently mounted to the workpiece. Particularly, the tool fastened on the tip of the transduceras pointed out hereinafter-is welded or clamped' to the workpiece. But again, although there is direct contact, the addition of the work tool or adapter workpiece makes possible the delivery of high amounts of energy into relatively thin plates of work-surface material.

Specifically there is shown in FIG. 1 the tip of the horn of the transducer 5 being fastened at I9 to the work area 3. The work area 3 in this instance is a flat sheet. In operation the work motion applied to the work area 3 will be in the horizontal or planar direction as shown by the arrows. However, it is to be noted that the direction of coupling of the transducer 5 to the sheet 3 is neither in the horizontal or vertical directions to the sheet surface-it is at an angle somewhere between. Again in operation--the source power is effectively delivered by the transducer to the work surface. .The work surface is caused to move by each impulse in a direction not in line with the longitudinal axis of the transducer. Further the resonant frequency of the transducer is not matched to the many resonant frequencies of which the plate is capable. In this way there is effective coupling, permitting a flow of sonic energy from the transducer into the plate. The junction of the plate and the transducer presents an impedance mismatch to a sonic energy flow from the transducer. This junction therefore becomes an antinode, vibrating at maximum amplitude at the resonant frequency of the transducer and tool. The same junction does not present a major change in'impedance to the fiow of sonic energy within the plate at any of the many resonant frequencies of which the plate is capable. Therefore the transfer of sonic energy from the plate back to the transducer is minimized.

The arrangement shown in FIGS. 2 and 2a is similar to that of FIG. 1 except that the work area 3 in this instance is a tubular structure 3.

In the arrangement of FIG. 3 the tool 19 is of a hollow conical shape.'As pointed out relative to FIG. 1 the forward and return motion is in the planar direction-Le, as shown by the arrows. Hence in this embodiment the coupling of the transducer tip 10 is in a vertical direction to maintain spatial (outof-line) relationship-described above-between transducer and tool. 7

The arrangements shown in the various FIGS. have been adapted to earth-moving blades, penetrating solid materials, and for various drilling and riveting operations.

It is understood that modificationsand departures may be -had from the actual structures shown within the scope of the invention.

We claim:

1. In combination with a resonant high-power, high-Q electromechanical transducer having a longitudinally generally elongated element capable of transferring high-power energy to a workpiece, the improvement comprising means for fixedly positioning the tip of said elongated element to said workpiece, said means maintaining said elongated element in an out-of-line longitudinal relationship with the longitudinal axis of said workpiece.

2. The combination of claim I wherein said workpiece is a large area surface having resonant frequencies out of phase with the resonant frequency of said transducer.

3. The combination of claim I wherein said tip of said trans ducer further comprises a one-half wave extension. 

1. In combination with a resonant high-power, high-Q electromechanical transducer having a longitudinally generally elongated element capable of transferring high-power energy to a workpiece, the improvement comprising means for fixedly positioning the tip of said elongated element to said workpiece, said means maintaining said elongated element in an out-of-line longitudinal relationship with the longitudinal axis of said workpiece.
 2. The combination of claim 1 wherein said workpiece is a large area surface having resonant frequencies out of phase with the resonant frequency of said transducer.
 3. The combination of claim 1 wherein said tip of said transducer further comprises a one-half wave extension. 